Nematodes taking big bite out of cotton profits

What is in this article?:

• When it comes to nematodes, growers need to forget about getting rid of them and focus their attention on managing the tiny subterranean pests that can devastate a cotton crop before it gets started.

• Damage from nematodes in cotton often goes unnoticed or is attributed to a host of other diseases, nutritional or insect-related damage.

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COLUMBIA LANCE nematodes create extra problems for growers in the Carolinas and parts of Alabama and Georgia.

There is little doubt there will be plenty of cotton in the Southeast in 2012 and a good bet that prices will remain around the dollar a pound mark.

Taking care of the cotton crop in most soils in the Upper Southeast starts with taking care of an easy-to-miss problem — nematodes.

When it comes to nematodes, growers need to forget about getting rid of them and focus their attention on managing the tiny subterranean pests that can devastate a cotton crop before it gets started.

Nematodes are microscopic worm-like animals that feed primarily on the roots of cotton plants. Plant-parasitic nematodes puncture root cells with a sharp stylet and withdraw nutrition from the host plant.

The Society of Nematologists contends nematodes do about $3 billion in crop damage on an annual basis worldwide. They represent four out of every five animals on earth. They’ve caused as much as $81 million worth of damage annually to crops in a single state in the U.S.

Damage from nematodes in cotton often goes unnoticed or is attributed to a host of other diseases, nutritional or insect-related damage.

“The first three things growers need to do in managing nematodes are sample, sample, sample,” says long-time Clemson University Plant Pathologist John Mueller.

“If you don’t know what nematodes you have and how many you have, none of the tools we can recommend will mean much,” Mueller says.

“Saying you have a nematode problem in a cotton field is much like saying you have an insect problem — without knowing which one, it’s hard to manage it,” he adds.

Soil volume is critical when evaluating the results from a nematode sample. Some states express their results per pint of soil. Other states express their results “per 100 milliliters of soil”. Your local Extension agent or crop consultant can be sure the thresholds you use to interpret your results are for the proper soil volume.

Mueller, who doubles as Director of the Edisto Agricultural Research and Extension Center, says South Carolina and surrounding states have root-knot and reniform nematodes that are common in many Southeast states, but they also have Columbia lance nematodes, which aren’t nearly so common.